Expose metadata link to next version of the model

This PR adds a metadata field to link this model to a newer version of the same model family: microsoft/phi-2. This metadata field helps ensure people are using the latest version of your model.

If there are multiple version i.e. version 1, version 2 and version 3. Linking version 1 and 2, and 2 and 3 will mean the latest version is always shown. See https://huggingface.co/docs/hub/model-cards#specifying-a-new-version for more info.

Here is an example of what this looks like:


README.md

@@ -1,6 +1,7 @@
 ---
 license: mit
 license_link: https://huggingface.co/microsoft/phi-1_5/resolve/main/LICENSE
+new_version: microsoft/phi-2
 language:
 - en
 pipeline_tag: text-generation